N-acetylglucosamine: more than a silent partner in insulin resistance.

Pedersen et al. (Pedersen HK, Gudmundsdottir V, Nielsen HB, Hyotylainen T, Nielsen T, Jensen BA, Forslund K, Hildebrand F, Prifti E, Falony G, et al. 2016. Human gut microbes impact host serum metabolome and insulin sensitivity. Nature. 535: 376-381.) report that human serum levels of branched-chain amino acids (BCAA) and N-acetylglucosamine (GlcNAc) increase in proportion to insulin resistance. They focus on the microbiome and the contributing subset of microbe species, thereby demonstrating disease causality in mice. As either oral GlcNAc or BCAA in mice are known to increase insulin resistance and weight gain, we note that recently published molecular data argues for a cooperative interaction.